A vehicle structure is known in which a side member that extends in the longitudinal direction of a vehicle is provided on each side portion of the vehicle. The end portion of each side member has a crumple zone (i.e., a crushable zone) provided to absorb impact during a collision or the like. Also, a radiator is provided at the front of the vehicle. This radiator is supported by a radiator support, for example, which is provided so as to connect the crumple zones of both side members. If another vehicle or the like collides with a sub-frame that extends in the lateral (i.e., left-right) direction of the vehicle, such as this kind of radiator support or the like, the force of impact on the sub-frame will be transmitted to the side members where it will be absorbed at the crumple zones of those side members.
An example of this kind of vehicle structure is described in Japanese Patent Application Publication No. 2005-82020 (JP-A-2005-82020). In this vehicle structure, the entire sub-frame is fixed to the front end portion of the side members. If another vehicle or the like collides with the sub-frame, the force of impact from the collision will be transmitted to the crumple zones of the side members that are fixed to the sub-frame, where it will be absorbed.
However, with the vehicle structure described in JP-A-2005-82020, the sub-frame and the side members are entirely fixed to each other. Therefore, the strength of the portion of the crumple zones of the side members that is fixed to the sub-frame is greater than it is at other portions which may inhibit its ability to deform in the event that another vehicle or the like collides with the vehicle from the front of a side member. As a result, the crumple zone becomes that much narrower which reduces the ability to absorb the impact.
One conceivable way to solve this problem is to not fix the sub-frame to the side members. However, if the sub-frame was not fixed to the side members and another vehicle was to collide with the sub-frame and there was a large difference in height between the two vehicles, for example, the force of impact on the sub-frame would not be able to be transmitted to the side members, which would reduce the ability of the sub-frame to absorb the impact.